Hello everyone .Im looking for some help with running some drain pipe throughout a new horse barn that has just been framed out. Ive attached a rough sketch very rough, but hopefully you can get the idea. There are 6 horse stalls with drains in them and 4 drains spaced out in the main aisle. I also want to add a sink in the tack room. Im a novice when it comes to plumbing  I can tackle any task, but as far as materials and layout for this project, I need some help. I am going to be pouring a 4 concrete floor over the entire area. The drains will tie together (as shown in the drawing) and drain to a dry well.
My questions are:

- What size pipe do I need to use for each of the drains and what type of material?  PVC?
- Do I need the drains before I pour the concrete so I can attach them (without the grates of course) to the top of each pipe coming up to be flush with the floor?
- Im going to pitch the drain pipes ¼ per foot --- correct?
- These pipes just need to be under the ground and then pitched to whatever depth they are at the end of the run---correct? They do not have to start at a certain depth, do they?
- For the trenches  some kind of paper material, then gravel, lay the pipe, then gravel on top???
- What is the best fitting to use to tie in each drain pipe to the main line?
- For the sink  I will most likely be purchasing an electric hot water heater how do I run the lines from the water heater to the sink?  under or above ground?
- The barn is not insulated or heated how will the water lines for the sink not freeze in the cold weather?  Is there a way to specifically avoid this with a sink in the barn?
- What size pipe is best to run to the sink for water lines? And should I use copper or pex?
- 2 drain pipe for the sink I assume? And does the 2 pipe just tie into the main drain line or do I need to transition to the size of the main pipe? And obviously I dont need to vent this pipe as there is not a septic system in the barn  correct?
- Sorry for so many questions, but this will be a great help to me to get this started.
Thanks in advance!

Are you using concrete for the horse stalls? Are you going to also utilize shavings? If the answer is yes, you might want to reconsider having the drains with the horses. Unless the drains in the stalls are extremely secure, they can injure horses pretty easy. Also, are you planning on using auto-waterers? If so, I would stick with galvanized pipe as PEX and copper will quickly be eaten by the horses if they have access.

It looks like you are running two seperate lines the drain to two seperate areas so I will assume that. I would use SDR 35 PVC Pipe for all the underground portions (I install it daily for sewer and storm drain) I have attached a drawing but I would use 4" fopr the lateral and 6" for the main line portion, you could get away with 4" for all but there is a greater chance of it gettin blocked up. For the drains I would use 12" catch basins with ADA rated grates (they have smaller holes so less stuff and less problems for the horses) If you want to save a few bucks in that area you could just get the grates and weld an angle iron frame that you put into the concrete when you pour (Make sure you spray galvanize it) and on the inside just form the concrete to where it will slope into the drain. Cut your drains to the level you want before you pour because it is much easier than later. Also when installing the SDR 35 PVC Pipe it is bell by spigot so you will need to use pipe soap to lube the gasket so that it will slide together, if you cannot get the soap you can use dish soap as an alternative. One more thing when you put the pipe in make sure the spigot is down hill so there is less chance of things getting stopped up trying to get down the drain. Also they make and sell all the Why's and reducers you would need for your project. A couple nationwide suppliers of pipe are HD Supply and Ferguson waterworks. let me know if you need anything else.